Prince Charles: public duty v private power

As the prince's influence on political issues has grown, so has concern about the extent and transparency of his powers

Prince Charles and David Cameron chat at a reception at Clarence House. There is an absolute exemption on the release of details about Charles's contacts with ministers and senior civil servants. Photograph: Chris Jackson/Getty Images

Prince Charles has described himself as a meddling prince, but prefers to describe what he does as "mobilising". He told an NBC documentary crew in 2010 he felt "born into this position for a purpose", explaining: "I don't want my grandchildren or yours to come along and say to me: 'Why the hell didn't you come and do something about this?'"

So he has waded into the political sphere on pet topics, such as planning, the environment and medicine. He scrawls "black spider memos" to government ministers, calls secretaries of state into Clarence House for private conversations about policy, and writes confidential notes to high-level contacts to get planning matters changed.

As his influence has grown, so has interest in understanding how that influence operates. Anyone trying to find out quickly discovers that an edifice of state-enabled secrecy surrounds the prince's power.

In recent years, cracks have begun to appear and royal aides and ministers are now battling on several fronts to maintain discretion around Charles's interventions.

This autumn a seven-year campaign by the Guardian to expose some of Charles's letters to ministers in seven Whitehall departments enters its final stages. The government is resisting the application, which will be decided by a freedom of information tribunal. Ministers are relying on a "well-established constitutional doctrine that the heir to throne has a right and duty to be instructed in the business of government in preparation for the time when he himself will be the sovereign".

On the environment, the tribunal last year ruled that the Duchy of Cornwall must be considered a public authority and therefore should release information about its impact. The ruling stemmed from a request by environmental campaigner Michael Bruton, who was concerned about the Duchy leasing waters for farming Pacific oysters in the Lower Fal and Helford intertidal area in Cornwall. Bruton asked the Duchy what assessments it had made of the environmental impact of the lease. The Duchy refused to answer, saying it was a private estate. The judgment means that many of the activities of the estate that provides Charles with a £17m-a-year private income should be made public, although it is being challenged by the prince's lawyers.

In February the information commissioner ordered the release of a limited number of papers that show how the prince was consulted over the marine and coastal access bill, but it was decided many others should remain confidential.

The bad news for freedom of information campaigners is that rules on disclosure around royal dealings with government are getting tighter. Changes to the Freedom of Information Act in 2010 granted the heir to the throne an absolute exemption from the release of details about his contacts with ministers and senior civil servants.